Damn, the polish on this thing is pretty nice - the effects, opening intro, the in-game cutscenes; The game looks pretty and the music is very catchy.
The double-character spin is a nice twist for the genre but it makes also the game a bit tedious to play (it's the small things like requiring to press up to pick Lumi/ pressing down to drop and shift to switch; when dropping Lumi isn't placed where Light stands but is thrown instead). This becomes noticeable especially when the player needs to react fast like defeating shooting enemies. I wonder if this could be streamlined to make Light automatically pick-up lumi when near and shift to drop and switch. Platforming itself could also be more fleshed out (the characters move quite slow, the jump height is pretty limited and the combat range short).
Yet I couldn't score this game any lower than 4.5 - the polish is just so good on this one. With more effort I think this could be turned into a commercial project.